1 files changed, 124 insertions, 0 deletions
diff --git a/firmware/octoclock/lib/state.c b/firmware/octoclock/lib/state.c
new file mode 100644
index 000000000..0dbcc6ece
--- /dev/null
+++ b/firmware/octoclock/lib/state.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2014 Ettus Research LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <avr/interrupt.h>
+#include <avr/io.h>
+
+#include <debug.h>
+#include <octoclock.h>
+#include <clkdist.h>
+#include <state.h>
+
+void led(LEDs which, int turn_it_on) {
+
+    // selects the proper bit
+    uint8_t LED = 0x20 << which;
+
+    if(turn_it_on)
+        PORTC |= LED;
+    else
+        PORTC &= ~LED;
+}
+
+void LEDs_Off(void){
+    led(Top,false);
+    led(Middle,false);
+    led(Bottom,false);
+}
+
+void force_internal(void){
+    led(Top,true);
+    led(Middle,false);
+    led(Bottom,true);
+
+    setup_TI_CDCE18005(Primary_GPS);
+
+    // Set PPS to Primary (1) n.b.:  "1" in general means "Internal" for all
+    // such signals
+    PORTA |= (1<<PA6);
+}
+
+void force_external(void){
+    led(Top, false);
+    led(Middle, true);
+    led(Bottom, true);
+
+    setup_TI_CDCE18005(Secondary_Ext);
+
+    // Set PPS to External
+    PORTA &= ~(1<<PA6);
+}
+
+void prefer_internal(void){
+    // if internal is NOT OK, then force external
+    if(global_gps_present)
+        force_internal();
+    else if(global_ext_ref_is_present)
+        force_external();
+    else
+        LEDs_Off();
+}
+
+void prefer_external(void){
+    // if external is NOT OK, then force internal
+    if(global_ext_ref_is_present)
+        force_external();
+    else if(global_gps_present)
+        force_internal();
+    else
+        LEDs_Off();
+}
+
+static uint8_t prev_PE7 = 0;
+static uint32_t timer0_num_overflows = 0;
+
+ISR(TIMER0_OVF_vect){
+    global_gps_present = (PIND & (1<<DDD4));
+
+    // Every ~1/10 second
+    if(!(timer0_num_overflows % 610)){
+        prev_PE7 = (PINE & (1<<DDE7));
+
+        if(get_switch_pos() == UP) prefer_internal();
+        else prefer_external();
+
+        global_ext_ref_is_present = false;
+    }
+
+    if(!global_ext_ref_is_present){
+        global_ext_ref_is_present = (prev_PE7 != (PINE & (1<<DDE7)));
+    }
+
+    timer0_num_overflows++;
+}
+
+ref_t which_ref(void){
+    if(!global_gps_present && !global_ext_ref_is_present) global_which_ref = NO_REF;
+    else if(global_gps_present && !global_ext_ref_is_present) global_which_ref = INTERNAL;
+    else if(!global_gps_present && global_ext_ref_is_present) global_which_ref = EXTERNAL;
+    else global_which_ref = (get_switch_pos() == UP) ? INTERNAL : EXTERNAL;
+
+    return global_which_ref;
+}
+
+switch_pos_t get_switch_pos(void){
+    uint8_t portC = PINC;
+
+    // UP is prefer internal,
+    // DOWN is prefer external
+    return (portC & (1<<DDC1)) ? DOWN : UP;
+}